Magnetron electron discharge device



Oct. 21, 1952 w. c. BROWN MAGNETRON ELECTRON DISCHARGE DEVICE 2 SHEETS-SHEET 1 Filed July 17, 1946 Oct. 21, 1952 w c RQ 2,615,143

MAGNETRON ELECTRON DISCHARGE DEVICE Filed July 17, 1946 2 SHEETS-SHEET 2 perature.

tamed, briefly, in the iollowing manner..

Patented Oct. 21 1952 UNITED sTArE-s PATENT OFFICE MAGNE'TRON ELECTRON DISCHARGE DEVICE William C. Lincoln, Mass.,; 'as sig nor' to Raytheon Manufacturing Company, vNewton,

: ass'., a corporation of Delaware 7 I Application July, 1946, Serial No. 684,110 ll'Cla'ims. (01. 315-39) This .inventi on'; relates to, electron discharge ::devices and; more particularly, ,;to electron-dislchargegdevices, of the type known as multipleanodegmagnetrons. V ,7 s ;,;Such devices generally have frequency-icontrolling circuits incorporated directly therein; for

which reason their dimensions become prohibitively large when used, :for exam-plainthe middlegregion of the very-high frequency band of the electroma netic spectrum, ;such;-as .from t 100 to 200 megacycles, ThiS;lSf especially sso where such devices, are intended-for generating powe nof appreciable magnitude. 7 .v,

- Itis, therefore-the main object; of the present invention to provide an electron-discharge devices-of the general character indicated, f ornse at the frequencies to which referenceuhas been made; without requiring components-of impractical proportions. A

;It is a furthereobiect ofthepresentinvention so to construct. an electrons-discharge device of the above-mentioned typeas. to: enable theisame to handle appreciable power/without,overheatna yet requiring no elaborate,auxiliaryvmeans for maintaining; the same at a reasonable tem- These, and otherizobj ects orfthe presentinven- I .tion which willbecome-more apparent as the detailed description thereofiprogresses,ware at- ,Ihe electron-discharge .device of 1 the; present invention; contemplates the provision; f an envelope, preferably, of cylindrical form, and made,

preferably, .of magnetic;material,. such as steel. Axially,:dispo-sedwithin said envelope, and supported, .for .example, from 011610113118; end-walls thereof, ;l.S, a, cathode; and extending interiorly from .one r-both of theend. walls of said. envelope, longitudinally of; said envelope and .co-

axially, aboutsaid cathode, is a plurality of anode members. Preferably, each of said anode ,mem-

bers includes a fluid-receiving.elementjor coolingth-e same, said elementnommunicating with ,.theg;exte rior of the envelopei-n order to receive theflCOOl-illg fluid froma fluid supply channel common to: the fluid intakes of. all theUfluid-receiving elements and to exhaust ,the' fluid. @Such anarrangem'ent for-supplying fluidto the fluidreceiving elements willbe referred to herein by expressing the v fluidreceiving elements as be ing hydraulically in parallel. Each of said members iurther includes an electron-receiving; .ele-

.ment which is carried by said fluidereceivinglelement in spaced relationship a to the cathodepf the device; Said. anode members areof. such -55 tration only, inasmuch as changes therein may Physical lengthrand are so ;,spaced .from each other that each :pair .of adjacent :members, together withthe supporting portions ofthe wallof the envelope lying, therebetween, constitutes va transmission line whose electrical length is such that it is resonant at the frequency desired of the output of the device.

Astwill later i be described in greater detail, the

- present invention may take more; than a one form. In one of these. f0rms,.the anode-members are supported from opposite end walls oft-the; en-

velope and arepfianelectrical length substantiallyequalto the.length of a. half-waveat the-rest nant frequency =iof" the device; In; this: case,= the electron-receiving elements are carried by q the fluid-receiving elements midway alongthelength of the latter,. sothat each pairhofvadjacent anode members, together, with the envelope wall portions therebetween, defines a, pair of parallelconnected, shorted 'quarterewave transmission linesradaptedtoresonate at the output frequency of the ,device.

In; anotherx-form of the present invention, the

anode members are supported 0n1y:fl'0m;0l1e 0f 25.

theendwalls of the envelope, the fluid-receiving element of :each anode member being closed at its inner end, and open at its outer end ,to communicate with theexteriorof the.-envelope.- .'Ihe

electron receiving elements are; carried by the fluid-receivingelements adjacent ;-their inner closed ends; and in this case the electricallength of each .fluidreceiving-element; is substantially equal to the length'oi aquarter-wave-atthe resonant; frequencyuof thedevice, whereby :each

pair of adjacent anodemem'bers; together' with that portion of the, supporting wall -;of thee-nvelope lying therebetween, constitutes. a shorted,

-q.uarter-wave transmissionline. I

Each ,of the embodiments above referredto is completed by a .pairof opposed magneticpole piecessupported by the opposite endwallsfzof the envelope, said pole pieces beingadapted to establish a magnetic field stransversely of the ,electron path I between the Y cathode and anode .members of :the device, theenvelope, in-one of ,said embodiments of; the-device, constituting a .return pathforthemagnetie-flux.

In the accompanyingspecification :-there;sha11 be described, and in theannexed drawings shown,

two illustrativeembodiments of the electron-discharge devices of the present invention. .,It.is, however, to be clearly understood that-.therpresent invention, is notto belimited to the details herein shown and described for. purposesvof illusbe made without the exercise of invention, and within the true spirit and scope of the claims hereto appended.

In said drawings, Fig. 1 is a longitudinal sectional view taken substantially through the center of the first of the embodiments of the electron-discharge devices of the present invention above briefly described; and

Fig. 2 is a similar view of the second of the embodiments of the present invention above briefly described.

Referring now more in detail to the embodiment of the present invention shown in Fig. l of the drawings, the numeral it} designates a hollow tubular, for example, cylindrical body closed at its ends by end plates I I and I2, said body and end plates constituting a hermetically sealed envelope made, preferably, of magnetic material, such as steel.

Centrally disposed within said envelope is a cathode sleeve l3 made, preferably, of nickel, said sleeve being provided, adjacent its inner end, with spaced shields 54 intermediate which said sleeve is provided with an electron-emissive coating i5, for example, of the alkaline-earth metal oxide type. The sleeve i3 may be supported from one of the end plates H or E2, here shown as the end plate [2, by securing the same to a bushing 55 to which is afllxed an insulator I! the opposite end of which is affixed to a ring l8 carried by the end plate i2. The bushing iii and the ring it are made, preferably, of the material known as Kovar, and the insulator li may be made of glass. Thus, the cathode structure is electrically isolated from the envelope structure.

A cathode heater is is mounted within the sleeve L3 as by-having one end 26 thereof electrically connected to the upper shield i l and the other, lead-in end 2i, thereof passing downwardly through said sleeve and being supported therein by glass beads 22 and 23. Current may be supplied to the heater is by connecting, one end of a voltage source (not shown) to the sleeve IS, the other end of said voltage source being connected to the lead-in end 2! of said heater. 7

Supported from the end plates l! and i2, extending longitudinally of the cylindrical body H3, is a plurality of anode members 2%, said. anode members being uniformly spaced from each other and concentrically disposed about the cathode sleeve l3. Each of said anode members includes a tubular, fluid-receiving element 25 made, preferably, of cop er, and being of a length corresponding to that of a half-wave at the frequency desired of the output of the device. Carried by each of said fluid-receiving elements, at a point midway along the length thereof, so as to face the coated portion 55 of the cathode sleeve is, is an electron-receiving block 26 made, preferably, of copper. The arrangement is such that the upper and lower halves of each pair of adjacent anode members, together with those portions of the end plates H and I2 lying, respectively, therebetween, constitute parallel-connected, shorted quarter-wave transmission lines which are resonant to the output frequency of the device.

In order to dissipate the heat developed in the anode members 24, the tubular elements 25 thereof communicate at their ends with toroidal headers 21 and 28, the former receiving a cooling fluid, such as water, from an inlet pipe 29, and the latter expelling said fluid, after the same has passed through the elements 25, by way of an outlet pipe 38.

In order to establish a magnetic field in a direction perpendicular to the electron path between the cathode !3 and the anode members 2d, with which devices of the magnetron type are usually provided, the end plates H and I2 carry inwardly extending tubular magnets 3| and 32 of opposite polarity, said end plates and the cylindrical body It] therebetween providing the return path for the flux of said magnets.

The device is completed by a conductor 33 electrically connected to any one of the anode members 2%, said conductor passing through a pipe 3 1 threadedly engaged in the cylindrical body it. The conductor 33 and the pipe 34 constitute, respectively, the inner and outer conductors of a coaxial transmission line by means of which the oscillations generated Within the device may be conveyed to any utilization circuit.

Reference is now had to the embodiment of the present invention shown in Fig. 2 of the drawings. As there shown, the device comprises an envelope consisting of a cylindrical body 35 closed at one end by an end plate 36 and carrying near its other end a plate 31, in this case,

made, however, of copper.

Axially disposed in said cylindrical body 35, and supported from the plate 3'2, is a cathode sleeve 38 made, preferably, of nickel, said sleeve being provided, at its inner end, with a pair of spaced shields 39 between which said sleeve is coated, as at d8, with an electron-emissive material, for example, the oxide of an alkalineearth metal. The sleeve 38 is fixed in a bushing ll sealed to the lower end of an insulator 42, the upper end of said insulator being sealed to a ring 33 carried by a flanged, tubular pole piece 44 which extends into the envelope through a central opening in the end plate 36 thereof. The bushing ti and the ring 43 may be made of the material known as Kovar, and the insulator 42 may be made of glass.

The cathode sleeve 38 is provided with a heater st one end 55 of which is electrically connected to the upper shield 39, and the other, lead-in end 56, of which passes downwardly through said sleeve I58, being spaced therefrom by a glass bead 2?. Thus, current may be supplied to the heater i t by connecting the sleeve 38 to one terminal of a voltage source (not shown), and connecting the lead-in end 46 to the other terminal of said voltage source.

Extending downwardly from the plate 37, uniformly spaced from each other and concentrically disposed about the cathode sleeve 38, is a plurality of anode members 48 made, preferably, of copper, each comprising a tubular, fluid-receiving element d9, open at its upper end and closed at its lower end, each such fluid-receiving element carrying, adjacent its lower end, an electron-receiving block 56. Each anode member 48 is of such physical length that each pair of adjacent members, together with that portion of the plate 3? lying therebetween, constitutes a shorted, quarter-wave transmission line at the frequency desired of the output of the device.

The plate 3?, together with a ring 5|, seated upon the cylindrical body 35, and an end plate 52, provided with a magnet-receiving socket 53 extending into the envelope through a central opening forward in said plate 3?, constitute a header divided into incoming and outgoing fluidreceiving compartments by a baflie 54. The baffle 54- carries a plurality of pipes 55 which comaar-5,1143

' mane "with thei' u-pper" or incoming fluid -reeivlng compartment of the header,z:and 'which extend downwardly into the "fluid-receiving: eleff-inents 49 of the-anode-members '48; 'saidi pipes being-open at=their lowerends and terminating sh'ort of "the closedends -ofsaid fluid receivin ele'ments-- 4 9. A i coming sum; such as water;- enters the header through *an' inletpipe 5 6, 1 passes v 'to "the --e1emems4s through-the"pipes--55-;' enters the-lo'weror outgoing compartment of the header "iro'm the "upper-- openends of 'said elements' 49,

and *leaves' the device'through an outlet pipe 51.

established *in thespace bet-ween the Cathode tricallyco'nnected"to 'the tubular-element 49' of any one of the anodemembers acz'said conductor passingoutof thedevice through the cylindrical body 38 and constituting, together with a pipe 6|, threadedly engagedcinisaid cylindrical body, a

coaxial transmission line for conveying the oscillations generated insaid device to any utilization circuit.

This completesithef descriptioni of; the aforesaid-illustrative embodiments of the present in- 'vention.- It will be notedlfrom-all oftheiorel; going that; by reason of the .disposition or the 3 anode members within the envelope the'l device is readily-adapted for use at frequencies. in the middleregion of the very-high frequency band o'f the Spectrum, and'that the components making up the device are 'of-p'ractical proportions. It willsfurther be noted that, by reason of the aforesaid.arrangement. of the .anode 'members fr "within the. envelope, and the simple manner of cooling said anode members, the devices are capable of handling appreciable power without overheating.

These, and other objects and advantages of the present invention, will readily occur to those skilled in the art to which the same relates.

What is claimed is:

1. An electron-discharge device comprising: a cylindrical envelope; a cathode axially supported within said envelope; and a plurality of anode members extending interiorly from an end wall of said envelope; said anode members being disposed longitudinally of said envelope, circumferentially about said cathode; each of said anode members including a fluid-receiving element communicating, hydraulically in parallel with the fluid-receiving elements of the other anode members, with the exterior of said envelope, and an electron-receiving element carried by said fluid-receiving element in spaced relationship to said cathode; each pair of adjacent anode members, together with that portion of said end wall of said envelope lying therebetween, constituting a transmission line whose electrical length is such that it is resonant at the frequency of the output of said device.

2. An electron-discharge device comprising: an envelope; a cathode supported within said envelope; and a plurality of anode members extending interiorly from opposite walls of said envelope; each of said anode members including a fluid-receiving element communicating, hydraulically in parallel with the fluid-receiving elements of the other anode members, with the exterior of said envelope, and an electron-receiving -:element -.carried;. midwayaleng ,therlength? of said fluid-receiving element .in..spaced-relat ion- 1 ship to said'cathode; eachpair ofxadjacent anode -members together withthoseportions of said-opposite walls of said: envelopeilyingztherebetween.

r constituting a pairof :parallel-connected;zquarter=wave 'transmissionllines :adaptedatomescnate I at. the frequency. of the: output loflsaidadeviceh 3. :An -electronedischargeldevice .comprising: i a

cylindrical envelope; .a cathode supportedxlwithin i said envelope rand a' plurality ofianode .members extending interiorly-from oppositeend wallsgiof said: envelope; said: anode 1.members;:being..;disposed' longitudinallyi Of? saiduenvelope, circumferentially :aboutsaid; i cathode each :a'of said --.anode. .members .iincluding ,.acfluidereceiving ,ele- :ment. communicating hydraulically; in para each end thereof with the exterior of saidrienvelope, rand; an. .electron-{receivingelementpartried midwayrtalong; the :length; oi said fipid receiving element, in, spaced relationship ,1 to. said -.:cathod.e; rach; p r; of: adjac nt. ene e im mhe together with those'portions.ofsaidppposite end ywalls of said envelope,.lyi ge'fiherebetween, con- .---stituting a pair ofiparallel-connected ,quarter- ,,-wave transmission. ,lines adapted to ,resonateyat the frequency; of; the; output ofsSaid device.

4.. An'electron-discharge device-comprising: a

- cylindrical envelope ofmagnetic. material;,. a cathode supported within said. envelope; aplurality of anode .members, extending interiorly from pppositeendwalls of, said envelopeand a -pair of pole piecessupported inwardly of sfaid ...envelope by the wall of said envelope and adapted toestablish amagnetic field transverselyflof the electron path between said ,cathode and ,said

. anode members; said anode. members bein .dis-

posed longitudinally of .said, envelope, coaXially about said cathode; ,all, .of. saidanode members including separate fiuidereceiving elements .communicating at each end thereof with the exterior of said envelope, said fluid-receiving elements being connected hydraulically in parallel, and an electron-receiving element carried midway along the length of said fluid-receiving element in spaced relationship to said cathode; each pair of adjacent anode members, together with those portions of said opposite end walls of said envelope lying therebetween, constituting a pair of parallel-connected, quarter-wave transmission lines adapted to resonate at the frequency of the output of said device.

5. An electron-discharge device comprising: an envelope; headers mounted on said envelope and having, respectively, fluid inlet and outlet ports; a cathode supported within said envelope; and a plurality of anode members spaced from and surrounding said cathode; each of said anode members including a fluid-receiving conduit communicating at its ends with said headers; each pair of adjacent fluid-receiving elements, together with those portions of said headers lying therebetween, defining a half-wave transmission line shorted at both ends and being resonant at the frequency of the output of said device.

6. An electron discharge device comprising a source of electrons, a signal wave transmission network spaced from said source, said network comprising a pair of spaced substantially parallel conductors, a plurality of substantially parallel conductive members connected between said conductors, each of said conductive members having a passage therethrough, one end of each of said passages communicating with a common fluid supply source, and means for di- 7 recting electrons from said source along paths adjacent said network.

7. An electron discharge device comprising a source of electrons, a signal wave transmission network spaced from said source, said network comprising a pair of spaced substantially parallel conductors, a plurality of substantially parallel conductive members connected between said conductors, each of said conductive members having a passage therethrough, one end of each of said passages communicating with a common fluid supply channel for feeding fluid in parallel to each of said passages, and means for directing electrons from said source along paths adjacent said network comprising means for producing a magnetic field in a direction substantially transverse to the direction of motion of said electrons.

8. A signal wave transmission network comprising a pair of spaced substantially parallel conductors, a plurality of substantially parallel conductive members connected between said conductors, each of said conductive members having a passage therethrough, one end of each of said passages communicating with a common fluid header, and an additional channel for connecting said header with a fluid supply source.

9. A signal wave transmission network comprising a pair of spaced substantially parallel conductors, each of said conductors having a channel therethrough, a plurality of substantially parallel conductive members connected between said conductors, each of said conductive members having a passage therethrough, each of the passages in said conductive members being connected to the passages in said conductors, and means for supplying said channel in one of said conductors with fluid whereby fluid is supplied hydraulically in parallel to said passages.

10. An electron discharge device comprising a source of electrons, a signal wave transmission network spaced from said source, said network comprising a plurality of spaced conductors having passages therethrough, one end of each of said passages communicating with a common fluid supply channel, a passage for connecting said common fluid supply channel with a. source of fluid, and means for directing electrons from said source along paths adjacent said network.

11. An electron discharge device comprising a source of electrons, a signal Wave transmission network spaced from said source, said network comprising a plurality of spaced conductors having passages therethrough, one end of each of said passages communicating with a common fluid supply channel, a passage for connecting said common fluid supply channel with a source of fluid, and means for directing electrons from said source along paths adjacent said network comprising means for producing a magnetic field in a direction substantially transverse to the direction of motion of said electrons.

WILLIAM C. BROWN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,054,126 Hollmann Sept. 15, 1936 2,201,216 Baier et al. May 21, 1940 2,422,465 Bondley June 17,- 1947 2,428,193 Blewett Sept. 30, 1947 2,440,851 Donal May 4, 1948 FOREIGN PATENTS Number Country Date 443,077 Great Britain Feb. 20, 1936 509,102 Great Britain July 11, 1939 

